1. Field of the Invention
The present invention relates to a liquid jet head including piezoelectric elements each composed of a lower electrode, a piezoelectric material layer, and an upper electrode and relates to the piezoelectric element.
2. Description of the Related Art
A piezoelectric element that is used in, for example, a liquid jet head is an element in which a piezoelectric material film made of a piezoelectric material having an electromechanical transduction function is disposed between two electrodes. The piezoelectric material film is configured of, for example, crystallized piezoelectric ceramic.
An example of the liquid jet head including such piezoelectric elements is an ink jet recording head structured in a manner such that part of a pressure-generating chamber communicating with a nozzle orifice for ejecting ink droplets is constituted of a vibrating plate and the piezoelectric element deforms the vibrating plate so as to apply a pressure to ink in the pressure-generating chamber, so that ink droplets are ejected from the nozzle orifice. There are two types of ink jet recording heads in practical use: one employs a longitudinal vibration-mode actuator in which a piezoelectric element expands and contracts in an axial direction, and the other employs a flexural vibration-mode actuator. In order to arrange these actuators at a high density, piezoelectric elements that can obtain a large magnitude of strain by a small deriving voltage, i.e., piezoelectric elements that give a large magnitude of displacement are required.
Furthermore, Japanese Unexamined Patent Application, Publication No. 2006-278835 discloses a piezoelectric material layer of which X-ray diffraction peak position is regulated for improving the displacement characteristics of the piezoelectric material layer.
However, satisfactory piezoelectric characteristics could not be obtained even if piezoelectric elements with such a high dielectric film were employed. In addition, this problem is not limited to liquid jet heads represented by ink jet recording heads and is similarly present in other actuator devices.